Superman destroyed a spaceship right above the city and let it fall over it. I'm no even saying anything about how good/bad that is, but he did do quite some damage there.

The space-ship crashed on a few abandoned buildings, the buildings were in the area where Black Zero had flattened out a few blocks of the city.

Supes did not let it crash on buildings full of people, that part of Metropolis was already cleared.

After all, why would anyone stay in the buildings where an alien ship is causing destruction and where fighter jets are firings missiles over that ship ? (And all this happened before Supes came back into Metropolis.)

Those who are making such baseless complaints need to see the movie again.